With the usual disclaimer applying, from my experience in RHO there is--most of the times--a dedicated C/*G check-in counter. Perhaps because there are several A3/OA flights per day, perhaps because it's one of the few domestic flights that offers C class, check-in and baggage drop has usually been quite smooth there. Do not expect to find any lounge there of course, and prepare yourself for a quite hectic boarding, especially in summer months... Sometimes there is not even a discernible queue, let alone priority boarding. Especially if you are walking directly to the plane (no bus), then expect a crowd storming the plane to the front and the rear.

In low seasons though things are much more civilized, and often times you even get priority boarding.

Addendum: I have never flown so early in the morning from RHO, so I do not know how if things work differently in the small hours.